Darius was one of several League of Legends champions to be reworked during the 5.16 "Juggernaut" patch. It seems that more often than not when Riot reworks a champion they end up simply ruining them – either by making them overpowered or by severely underpowering them then having to subsequently shore them in up a future patch. Unfortunately, Darius has fallen victim to the balancing team.
TNS: "A League of Legends game mode, Arena, will return with some major changes that may breathe some life for a stagnant game."
ESTNN writes: "Hwei, LeBlanc and Ryze stand above the rest as the strongest players in the League of Legends 14.8 mid-lane due to substantial buffs in their scaling, base damage and crowd control (CC) respectively."
ESTNN write: "Our updated guide on the latest champions coming to Summoner's Rift."